Emboli guarding device

ABSTRACT

A device including a stent structure or frame to which a sheet is attached for use in minimizing or preventing emboli, particles, and/or air bubbles from migrating into certain areas of the anatomy. The device can be placed in the blood stream in an area of the heart, such as the aortic arch, to direct particles toward the descending aorta rather than toward the brain. The sheet of the device can be a thin film material, which may include multiple fenestrations that are smaller in size than the particles that are to be filtered.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. §119(e) of U.S.Provisional Patent Application No. 61/099,935, filed Sep. 25, 2008,which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to devices and delivery systems that canhe used in heart structures for the prevention of strokes. Moreparticularly, the invention relates to devices, methods, and deliverysystems for preventing undesirable movement of emboli within a heartstructure.

BACKGROUND

Large or small embolic particles or emboli can be formed for a number ofreasons in the left atrium or in other parts o f the heart, such as canoccur when surgically implanting prosthetic devices into a patient'sanatomy. When such particles or emboli are present in the atrium, theyhave the potential to migrate toward the brain at the arch of the aorta,and can thereby impose potential risk of stroke. Thus, there is a needto provide devices and delivery systems that can filter or guard againstundesired emboli migration within the heart or other bodily structuresof a patient.

SUMMARY

This invention provides devices, methods, and delivery systems that canbe used to prevent or minimize the possibilities of a person having astroke due to litigation of emboli, particles, and/or air bubbles intoundesired areas of the anatomy. The device accomplishes this bydirecting particle flow in a bloodstream in such a way that anyparticles within that bloodstream are directed along a path where suchparticles will not be detrimental to the health of the patient. Oneembodiment of the invention includes a device that consists of a stemstructure or frame to which a Nitinol thin film or pericardial sheet isattached in at least one area. The Nitinol thin film or pericardialsheet can be affixed diametrically across the stent, diameter at adistal segment of the stent, in one embodiment, although it is alsopossible that the device includes different placement a the film orsheet and/or that the device includes multiple areas having a film orsheet. Fenestrations with various desired dimensions can be created onthe thin film to allow blood to flow through it. If necessary, sidechannels between the film or pericardial sheet and the all of thestructure in which the device is located can also be created.

The stent structure or frame of the device can be used to anchor thedevice into the arch of an aorta, for example. In this way, when emboliflow through the aortic arch, the thin film or pericardial, sheet of thedevice can block the flow of emboli toward the carotid arteries or othercerebrovascular structures, and instead allow their movement with theblood flow to carry emboli toward the descending aorta. Thus, the use ofthe device of the invention can help to prevent brain stroke for apatient.

The devices of the invention can be percutaneously delivered using atranscatheter delivery system to a location in a patient, such as aorticarch. These devices can also be retrieved using a transcatheterretrieval device if needed. The emboli guarding devices can be used as apermanent implantable device at the aortic arch to prevent brainstrokes, or as a temporary deice to prevent brain stroke during anyprosthetic device implantation or a transcatheter valve deployment, forexample.

In another aspect of the invention, a guide catheter is provided, whichincludes an embolic filter positioned between its proximal and distalends. The filter can be positioned in a desired location in a patient toprovide particle filtration. In another aspect of the invention, anembolic guard centering delivery system is provided, which includes anexpandable mesh portion that can provide both embolic protection and acentering function. In yet another aspect of the invention, a guidecatheter with an expandable mesh portion is provided. The mesh of theguide catheter can provide both embolic protection and a centeringfunction to a device through which other devices, such as deliverysystems, can be advanced to a desired anatomical location.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further explained with reference to theappended Figures, wherein like structure is referred to by like numeralsthroughout the several views, and wherein:

FIG. 1 is a schematic cross-sectional front view of an emboli guardingdevice of the invention positioned within a heart structure;

FIG. 2 is a front view of an embodiment of an emboli guarding device,including a film or sheet including small fenestrations;

FIG. 3 is a front view of another embodiment of an emboli guardingdevice, including another embodiment of a film or sheet including smallfenestrations;

FIG. 4 is a front view of another embodiment of an emboli guardingdevice of the invention positioned within a schematic heart structure;

FIG. 5 is a front view of another embodiment of an emboli guardingdevice on a delivery system within a heart structure, with aself-expanding mesh structure in a collapsed condition;

FIG. 6 is another front view of the emboli guarding device of FIG. 5,with the self-expanding mesh structure in an expanded condition withinthe heart structure;

FIG. 7 is a front view of another embodiment of an emboli guardingdevice on a delivery system within a heart structure, with a meshstructure in a collapsed condition; and

FIG. 8 is another front view of the emboli guarding device of FIG. 7,with the mesh structure in an expanded condition within the heartstructure.

DETAILED DESCRIPTION

Referring now to the Figures, wherein the components are labeled withlike numerals throughout the several Figures, and initially to FIG. 1,one embodiment of an emboli guarding device 10 is illustrated in anexemplary, position within the anatomy of a patient. In particular, thedevice 10 is shown here as being positioned within an aortic arch 12,between the ascending aorta 14 and the descending aorta 16. Multipleparticles or emboli 20 are illustrated as being randomly dispersedthroughout the stream of blood. These particles 20 tend to flow in themain flow stream, which is indicated with arrow 22 in the area of theascending aorta 14 and with the arrow 24, which is on the opposite sideof the device 10 and in the area of the descending aorta 16. The emboliguarding device 10 alters the flow direction and guides emboli 20 and/orair bubbles carried by the flow stream toward the descending aorta 16,rather than toward the head vessels 26 (i.e., the brachiocephalic trunk,the left common carotid artery, and the left subclavian artery) and inthe direction of arrows 28, Such an alternative flow of emboli 20 canthereby help to prevent potential brain strokes and/or minimize thechances of migraines and other health issues. It is noted that theemboli and/or air bubbles within the blood stream can be created in, avariety of manners, such as from atrial fibrillation (AF), fromprosthetic heart valves, from left ventricular assist devices (LVAD's),and/or from any other sources of emboli.

Referring also to FIGS. 2 and 3, one embodiment of an emboli guardingdevice 10 consists generally of a frame 30 and a sheet of material 32that is positioned generally across its upper portion. The frame 30 maybe made of a material that is capable of being compressed and expanded,which can be advantageous for percutaneous delivery of the frame 30 toits desired location within the heart. In one example, the frame 30 ismade of a material that is expandable via the application of anoutwardly directed internal force, such as the force that can be appliedwith an expandable balloon positioned within the internal opening orarea of the frame 30. In another example, the frame 30 is made from aself-expanding material, such as a Nitinol mesh material. In this way,the device 10 can be compressed, to a size that allows it to bedelivered percutaneously to the desired location via a delivery system,and then allowed to expand by removing or retracting a compressivesheath, for example.

The materials from which the frames 30 of the invention are generallymade include a series of wires arranged into, a generally elongatedtubular support structure. The structure can include one or more linearportions and/or one or more curved, bent, or otherwise shaped portions,in order to provide an optimal fit within area of the heart. The supportstructure of the frame 30 may either be made up of a number ofindividual struts or wire segments arranged and secured to each other.Alternatively, the frame 30 may instead be formed from a single piece ofmaterial (e.g., a tube of material that is machined to provide, adesired structure configuration). That is, in one exemplary embodiment,the frame 30 may be laser cut from a single piece of material or may beassembled from a number of different components.

As described above, the frames 30 of the invention can be compressibleto a relatively small diameter for percutaneous delivery to the heart ofthe patient, and then are expandable either via removal of externalcompressive forces (e.g., self-expanding frames), or through applicationof an outward radial force (e.g., balloon expandable frames). In afurther alternative, some portions of the frame 30 may be self-expandingwhile other portions of the same frame are expandable throughapplication of an externally applied force. In yet another alternative,the frames of the invention can be self-expandable from a contractedstate to an expanded state via the application of beat, energy, and thelike.

Methods for insertion of the emboli guarding devices of the inventioncan include delivery systems that can maintain the frames in theircompressed state during their insertion and allow or cause all orspecific features of the flames to expand once they are in their desiredlocation. In addition, delivery methods of the invention can furtherinclude features that allow the emboli guarding devices to be retrievedfor removal or relocation thereof after they have been deployed fromtheir delivery systems. The methods of the invention may includeimplantation of the devices using either an antegrade or retrogradeapproach. Further, in certain approaches for delivering the devices 10of the invention, the devices can be rotatable in vivo to, allow thestent structure to be positioned in a desired orientation. In oneembodiment, a portion of the device 10, such as the frame 30, caninclude a radiopaque, echogenic, or MRI visible material to facilitatevisual confirmation of proper placement of the frame 30 relative to theanatomy of the patient. Alternatively, other known surgical visual aidscan be incorporated into the frame 30, if desired.

In another alternative embodiment, the device 10 can be delivered to thepatient's anatomy via a minimally invasive surgical incision (i.e.,non-percutaneously). In yet another alternative embodiment, the device10 can be delivered via open heart/chest surgery.

The frame 30 of the device 10 is generally tubular in shape, defining aninternal area that extends from a first end 34 to a second end 36. Theinternal area is essentially surrounded by the frame 30 and the sheet ofmaterial 32. The frame 30 can be configured to have an arc portion 38that is designed and/or chosen to generally match the anatomy of theaortic arch of the patient in order to keep it from being dislodged onceit is in place. Thus, the frames can be provided in various lengthsand/or shapes to accommodate the different sizes and/or shapes ofdifferent patient anatomies. While the exemplary frames 30 of FIGS. 2and 3 are similarly configured, the frame 30 of FIG. 3 includes anextension portion 39 at its second end 36 that, can provide additionalanchoring capability relative to the vessel in which it is positioned. Aframe, may include one or more extensions of this type and/or otherfeatures that provide such an anchoring capability.

The material or materials from which the sheet of material 32 is madecan vary widely, but generally include a relatively thin piece ofmaterial, such as pericardium or a polymer sheet, for example. Inanother alternative, a thin piece of Nitinol material can be used. Withany of these materials, a number of fenestrations or openings 40 can beprovided across the area of the sheet 32, as illustrated in FIGS. 1 and2 These fenestrations 40 can be sized to be smaller than approximately60μ, although the fenestrations can be any size that allows some bloodflow through the surface of the sheet 32 while blocking the movement ofthe emboli 20 through the sheet 32. Thus, the size of the fenestrations40 can be selected to effectively filter a size of emboli or particles20 that would be detrimental to the health of a patient if they were tomove through the sheet 32 in the direction of the arrows 28.

One method of delivering the device to a desired location in a patientis via percutaneous device insertion. In general terms for thisexemplary, delivery system, a transcatheter assembly can be provided,including a delivery catheter, a balloon catheter, and a guide wire. Thedelivery catheter can be of a type known in the art that defines a lumenwithin which the balloon catheter is received. The balloon catheter, inturn, can define a lumen within which the guide wire is slidablydisposed. Further, the balloon catheter can include a balloon that isfluidly connected to an inflation source. It is noted that if the framebeing implanted is a self-expanding type of frame, the balloon would notbe needed and a sheath or other restraining means would instead be usedfor maintaining the frame in its compressed state until deployment ofthe device. In any case, the transcatheter assembly is appropriatelysized for a desired percutaneous approach. For example, thetranscatheter assembly can be sized for delivery to the heart via anopening at a carotid artery, a jugular vein, a sub-clavian vein, femoralartery or vein, or the like. Essentially, any percutaneous intercostalspenetration can be made to facilitate use of the transcatheter assembly.

In the case of a balloon-expandable frame, once the frame 30 is properlypositioned relative to the anatomy of the patient, the balloon catheteris operated to inflate the balloon, thereby expanding the frame 30 tothe expanded state shown in FIG. 1. Alternatively, if the frame 30 isformed of a shape memory material, the frame can be allowed toself-expand to the expanded state of FIG. 1, such as by removing theexternal forces applied by a sheath. In either case, the frame 30 ispreferably expandable within the internal region of the implantationarea of the patient with sufficient outward radial force against theanatomical structure (e.g., the aortic arch area) that it cannot becomeunintentionally dislodged from this area of the patient.

The techniques described above relative to placement of the device 10within the heart can be used both to monitor and correct the placementof the device 10 in a longitudinal direction relative to the length,shape, and the like of the anatomical structure in which it ispositioned and also to monitor and correct the orientation of the device10 relative to any other structures that may also be implanted in thisarea.

It is noted that the emboli guarding devices 10 of the invention may bedesigned for permanent placement within the patient, or mayalternatively be removable after a certain period of time. In oneembodiment, the device 10 can be removed pertcutaneously, such as withthe use of a system that can recompress the frame 30 by a sufficientamount to remove it in this minimally invasive manner. In anotherembodiment, the device 10 may need to be removed in a more invasivemanner, such as via more conventional surgical techniques.

FIG. 4 illustrates an alternative embodiment of the invention, whichincludes an embolic guard guide catheter 60 that is shown as positionedwithin the aortic arch 66 of a patient. In this embodiment, the guidecatheter 60 includes an embolic filter 62 positioned between proximaland distal ends of the catheter 60. The embolic filter 62 can bedelivered to the desired location in the patient in order to providesimilar filtering features to those described above relative to FIGS.1-3. In this example, the catheter 60 can localize the embolic filter 62at the location of the head vessels 64. The length of the filter 62 canbe selected to achieve certain performance characteristics, such asbeing sufficiently long to span across the all of the head vessels 64.The filter 62 may include one or more areas having a thin film, whichmay or may not include fenestrations, as described above relative to thefilms that can be used in accordance with the invention.

FIGS. 5 and 6 illustrate another embodiment of the invention, whichincludes an embolic guard centering delivery system 80 that is shown aspositioned within the aortic arch 82 of a patient. In particular, FIG. 5shows the system 80 with a self-expanding mesh portion 84 in acompressed or collapsed condition relative to a delivery systemstability layer 86. Further, FIG. 6 shows the system 80 with the meshportion 84 in an expanded condition. In order to expand in this way, thestability layer 86 can be pulled proximally to release the mesh portion84, thereby allowing it to expand to the size and shape of the vessel inwhich it is positioned. In this way, the mesh portion 84 can provideembolic protection during delivery of a device. That is, the, meshportion 84 is made of a material or materials that allow blood flow, yetthat filter out emboli, particles, and/or air bubbles that areundesirably large. Further, the mesh portion 84 may comprise wiresand/or film materials that provide the desired level of particlefiltering. It is further noted that the expansion of the mesh portion 84provides a centering function for the delivery system 80 within theascending aorta. In this way, better coaxial alignment can occur betweena transcatheter valve that is being delivered via the delivery systemand the annulus during positioning and release thereof, for example.

Another aspect of the emboli guarding features of the invention isillustrated in FIGS. 7 and 8. In particular, a guide catheter 100 isillustrated as being positioned within an aortic arch 102 of a patient.FIG. 7 shows the guide catheter 100 with a self-expanding mesh portion104 adjacent to its distal end in a compressed or collapsed condition.In this Figure, guide catheter 100 can be driven over a guidewire (notshown) to position the device in a desired location above the aorticvalve in the ascending aorta. FIG. 8 illustrates the mesh portion 104 inan expanded condition. In order to expand the mesh portion 104 in thisway, an outer sheath 110 is pulled proximally to expose and thereforeexpand the mesh portion 104. A tip 108, which can be collapsible, of thedelivery system 100 can be pulled proximally out of the guide catheter100. This will provide an access channel through which another devicecan be inserted. For example, a delivery system can be advanced throughthe guide catheter 100 to a position adjacent to the aortic valve.

The mesh portion 104 can expand to the size and shape of the vessel inwhich it is positioned. In this way, the mesh portion 104 can provideembolic protection during delivery of a device (e.g., a transcathetervalve) and/or during balloon valvuloplasty procedures. That is, the meshportion 104 is made of a material or materials that allow blood flow,yet that filter out emboli, particles, and/or an bubbles that areundesirably large during other processes. Further, the mesh portion 104may comprise wires and/or film materials that provide a desired level ofparticle filtering. It is further noted that the expansion of the meshportion 104 provides a centering function for the delivery system 100within the ascending aorta. In this way, better coaxial alignment canoccur between a transcatheter valve that is being delivered via thedelivery system and the annulus during positioning and release thereoffor example. In this embodiment, once any other processes are completed,such as transcatheter valve delivery and deployment or balloonvalvuloplasty, the outer sheath 110 can be advanced in a distaldirection to collapse the mesh portion 104 for removal of the devicefrom the body.

The distal end of the guide catheter can also function to align and/ordirect a delivery system that is advanced within the guide catheter toan anatomical target, such as the aortic valve, for example. Providingthese capabilities of being able to more accurately align and direct thedelivery system can help to optimize the accuracy and reliability withwhich an implant or therapy can be introduced.

With either of the mesh portions described above relative to FIGS. 5 and6 or FIGS. 7 and 8, the mesh portions preferably are sufficiently sizedso that they can expand to match the size and shape of the vessel inwhich they are located. The mesh portions are also preferably made of amaterial that provides sufficient force against the walls of the vesselto prevent emboli from moving between the mesh portion and the vessel.Further, the mesh portions can additionally include one or more sectionsor areas, having a thin film or material that may or may not includefenestrations, such as is described above relative to FIGS. 1-3, forexample.

The present invention has now been described with reference to severalembodiments thereof. The contents of any patents or patent applicationcited herein are incorporated by reference in their entireties. Theforegoing detailed description and examples have been, given for clarityof understanding only. No unnecessary limitations are to be understoodtherefrom. It will be apparent to those skilled in the art that manychanges can be made in the embodiments described without departing fromthe scope of the invention. Thus, the scope of the present inventionshould not be limited to the structures described herein.

1-17. (canceled)
 18. A delivery system comprising a proximal end, adistal end, a self-expanding mesh portion adjacent to the distal end,and a moveable stability layer having an internal area within which themesh portion is containable, wherein the stability layer is proximallymoveable to release the mesh portion from the internal area of thestability layer, and wherein the mesh portion in its released conditioncomprises an outer diameter that is larger than an outer diameter of thestability layer.
 19. The delivery system of claim 18, wherein the meshportion comprises a filtration material.
 20. The delivery system ofclaim 19, wherein the filtration material comprises a thin film withfenestrations through its thickness.